Quantifying the risks of TB infection to cattle posed by badger excreta
Quantifying the risks of TB infection to cattle posed by badger excreta
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DOI：
10.1017/s0950268898001897
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发表时间：
1999-02-01
影响因子：
4.2
通讯作者：
Harris, S
中科院分区：
文献类型：
--
作者：
Hutchings, MR;Harris, S
尽管有强有力的间接证据表明，结核病从獾传播到牛的主要途径是通过受污染的獾排泄物，但尚不清楚相关的风险是否高到足以解释英格兰西南部疾病的流行。为了确定这是否是一种可行的传播途径，使用确定性方法研究了牛与獾排泄物的接触，以量化獾排泄物对牛造成的风险。牛和獾的尿液和粪便之间的调查和放牧接触水平可以解释英格兰西南部疾病的流行。从被感染牛分枝杆菌的獾尿污染的牧场中每咬一口的感染概率为3.7 × 10（-4），这可以解释英格兰西南部牛结核病的流行。每次调查的感染概率为6.9 x 10（-7），獾厕所的宠物咬伤为1.1 x 10（-7），这两个概率都可以解释西南部牛的结核病流行率。当只考虑英格兰西南部的高风险地区时，这些界限下降了8倍。然而，獾的排泄物仍可能对牛构成高度风险。牛与獾排泄物的接触水平远高于先前的设想，这表明每次与受感染的獾排泄物接触的感染概率对传播概率的影响更大，而不是接触水平，每次牛与受感染的獾排泄物接触的感染概率极有可能极低。
Despite strong circumstantial evidence to suggest that the main route of TB transmission from badgers to cattle is via contaminated badger excreta, it is unclear whether the associated risks ape high enough to account for the prevalence of the disease in south-west England. To decide whether this was a viable route of transmission, cattle contact with badger excreta was investigated using a deterministic approach to quantify the risks to cattle posed by badger excreta. Levels of investigative and grazing contacts between cattle and badger urine and faeces could each account for the disease prevalence in south-west England. An infection probability of 3.7 x 10(-4) per bite from pasture contaminated with badger urine infected with Mycobacterium bovis could account for the prevalence of TB in cattle in south-west England. Infection probabilities of 6.9 x 10(-7) per investigation and 1.1 x 10(-7) pet bite from badger latrines could each account for the prevalence of TB in cattle in the south-west. When considering only the high risk areas of south-west England these bounds fell by a factor of eight. However, badger excreta may still constitute a high level of risk to cattle. The levels of cattle contact with badger excreta are far higher than previously thought, suggesting that it is the probability of infection per given contact with infected badger excreta which has the greater influence on the probability of transmission and not the level of contact, The infection probability per cattle contact with infected badger excreta is in all likelihood extremely low.